2017 Grape Survey K. Buckley & M. Klaus 2017 Entomology Project Report - Plant Protection Division, Pest Program Washington State Department of Agriculture 2 May 2018 2017 Grape Survey Report Katharine D. Buckley & Michael W. Klaus, Washington State Department of Agriculture Summary The WSDA conducted a Grape Commodity Survey in 2017 to determine the status of invasive pests and diseases in Washington State affecting juice, wine and table grapes. Except for Grape Phylloxera, which is known to occur in Washington, no other target pests of this survey were found. Background Washington State is 2nd in the US in wine grape production with 55,445 acres currently in production (Mertz et al. 2017), which support over 900 wineries (washingtonwine.org). The impact of this wine industry on the state is estimated to be $4.8 billion (washingtonwine.org). Washington is also the largest producer of juice grapes (Honig et al. 2017) with 21,632 acres of primarily Concord and some Niagara varieties (Mertz et al. 2017). The value of these crops could decrease substantially if certain invasive pests established here. Additional pesticide sprays would be required, which would disrupt Integrated Pest Management (IPM) programs already in place. All of these pests and diseases are also restricted by various countries, making exports of vine stock, nursery stock and fresh fruit more difficult. 1 2017 Grape Survey K. Buckley & M. Klaus Light Brown Apple Moth (Epiphyas postvittana (Walker)) Light brown apple moth (LBAM) is a highly polyphagous species with more than 1,000 plant species including over 250 fruits and vegetables such as apples, citrus, corn, peaches, berries, tomatoes and avocados (Weeks et al. 2012). Larvae feed on buds, flowers and leaves, with most damage occurring due to fruit scarring and rotting from fruit feeding (Gilligan & Epstein 2014). LBAM is native to Australia, and has been introduced to Hawaii, Tasmania, New Zealand, and parts of Europe. It was found in California in 2006, with eradication efforts still ongoing (Lewis & Hodges 2010). Forewing patterning, especially on males, is highly variable, and is frequently misidentified when male genitalia are not used as the main diagnostic characteristic (Gilligan & Epstein 2014). European Grapevine Moth (Lobesia botrana (Denis & Schiffermuller)) European grapevine moth is the main grape pest in southern Europe (Stavridis & Savopoulou-Soltani 1998). Minor hosts in 27 different plant families include apple, sweet cherry, plum, peach, pear, roses, raspberry, and potato. Larval damage promotes numerous fungal rots, especially Botrytis cinerea (Sullivan & Breiter 2007). Though the likelihood of establishment in Washington is low, the risk of introduction is high. European grapevine moth was detected in Chile in 2008, and was discovered in California vineyards in 2009 where there are still quarantine restrictions, though it is considered eradicated there since August 2016 (Lucchi et al. 2014, USDA APHIS 2018). 2 2017 Grape Survey K. Buckley & M. Klaus European Grape Berry Moth (Eupoecilia ambiguella (Hubner)) The European grape berry moth causes similar damage and is native to the same areas as European grapevine moth. However, while the European grapevine moth may have three or more generations a year, the European grape berry moth only has two, with the second being the economically injurious one (Gilligan & Epstein 2014). It prefers cooler, moist climates (Frolov 2008) and could become established in western Washington, though it seems unlikely it would become a serious problem in arid eastern Washington. Summer Fruit Tortrix (Adoxophyes orana Fischer von Rösslerstamm) Summer fruit tortrix is a major leafroller pest of grapes, apples, pears and stone fruit in Europe and Asia, and feeds on more than 50 other plant species in other families (Gilligan & Epstein 2014). Direct larval feeding damage can be serious, and secondary fungal infections are common. As it prefers higher temperatures and high moisture, this insect is unlikely to establish in most of Washington, however, the potential economic and environmental damage if it were to establish is very high. Daktulosphaira vitifoliae Grape Phylloxera ( (Fitch 1855)) Grape Phylloxera is a native American grape pest that was once responsible for the almost complete destruction of the French wine industry (Riley 1874). Since then, nearly all major wine growing regions have used vines grafted on resistant American rootstock, with a few exceptions, including Washington State (Harbertson & Keller 2012). Grape Phylloxera are a microscopic aphid-like insect with a complicated life cycle (Riley 1874). The leaf form, which has not been found in Washington State, creates leaf galls that do not cause major issues with the plant. The root form, however, cause root galls and necrotic spots with 3 2017 Grape Survey K. Buckley & M. Klaus secondary fungal infections that cause stunting and death in European varieties of grapes (UC IPM 2018). Grape Phylloxera prefers clay soils, which most Washington wine grape growing regions lack. Due to this, while Grape Phylloxera may never become a major Washington pest, tracking its locations is still important in this area with a majority of self- rooted, non-resistant vines (Keller et al. 2012). History of Grape Phylloxera in Washington State The first record of Grape Phylloxera was in 1910 in Kennewick. The first confirmed record of Grape Phylloxera is from Vashon Island in 1943 (Haskett 1988). Following that, the WSDA began conducting nursey block inspections in 1987. After the program was expanded in 1988 to include areas outside of the nursery blocks, 8 locations tested positive, mainly around Wapato and the Tri-Cities areas (Haskett 1988). All nursery blocks again tested negative in 1988 and 1989 (Haskett 1989). Another WSDA survey was conducted in 2014, and 2 positive sites were found that year, one near Wapato, and one near Malaga in Chelan County (Klaus 2015). Australian Grapevine Yellows (Candidatus Phytoplasma australiense 16SrXII-B) Australian Grapevine Yellows (AGY) have been found in Australia, New Zealand, Israel, and Bolivia, and unlike the name suggests also infects papaya, periwinkles, chickpeas, pumpkins, cabbage trees, strawberries, alfalfa, peaches, red clover, beans and others (Sullivan & Breiter 2007). The causative agent is a mollicute, a type of prokaryote, which resides in the phloem tissue of infected plants. The Australian Grapevine Yellows are part of the aster yellows group phytoplasmas (Padovan et al. 1995). The only known vector of AGY is Oliarus atkinsoni, the cixiic planthopper, but some polyphagous psyllids, planthoppers and leafhoppers are also believed to be involved (Sullivan & Breiter 2007). Washington is considered to only be at moderate risk from this pathogen but with its broad range of hosts and trade restrictions there is cause for concern. 4 2017 Grape Survey K. Buckley & M. Klaus Flavescence dorée (Candidatus Phytoplasma vitis 16SrV-C) Flavescence doree phytoplasma is part of the elm yellows group (CABI 2017). It is currently only found in parts of Europe, although its leafhopper vector, Scaphoideus titanus, is now found throughout most of Europe and is native to North America. The presence of this vector is a threat, as any introduction of the pathogen may be efficiently spread from an infected source. As with many plant diseases, there is no cure, and control relies on prevention and vector control. Rotbrenner, Red Fire Disease (Pseudopezicula tracheiphila) 5 2017 Grape Survey K. Buckley & M. Klaus Rotbrenner is a fungal disease producing scorch-like symptoms on grape leaves. It is related to the North American pathogen P. tetraspora (angular leaf scorch), which causes similar symptoms (NSW DPI 2013). Rotbrenner is currently found only in Europe, and is especially common in France and Germany. It overwinters in dead leaves, and its wind and water-borne spores require several days of rainfall or high humidity at 15-20°C for infection of new growth to occur (NSW DPI 2013). Pierce’s Disease, Bacterial Leaf Scorch (Xylella fastidiosa) ‘Phony peach’ Normal Xylella fastidiosa is a xylem dwelling bacteria with almost as many common names as hosts. The strain that infects grapes is known as Pierce’s Disease, in plums it is Plum Leaf Scald, in peaches it is Phony Peach Disease, in citrus it is Citrus Variegated Chlorosis, and in trees including elm, oak, almond, coffee, and maple it is Leaf Scorch (Mizell et al. 2015). Over 30 families of plants, and 150 individual species are susceptible to X. fastidiosa. It is spread by xylem feeding leafhoppers, especially sharpshooters, and by grafting of infected material. It is widespread throughout southern Europe, the southeastern United States, and has been found in areas in California, Ontario, the Midwest and Mid- Atlantic States. It has recently become of great concern for the California wine industry with the introduction of the glassy-winged sharpshooter, an efficient and far-flying vector. There is no cure for X. fastidiosa, it kills in only a few years, and removal of infected trees is typically the only effective method of limiting its spread. 6 2017 Grape Survey K. Buckley & M. Klaus 2017 Grape Survey Objective The pest free status of Washington State will be maintained by early detection and possible eradication of an economically important group of insect pests. Washington State’s grape industries will be protected from an important group of destructive pest insects. The survey will help maintain the unregulated export of fruit from Washington State to international markets. Materials and Methods WSDA placed and monitored traps for four different species of moths, Grape Phylloxera, and four plant diseases (See Table 1), for the CAPS Grape Survey from June 21 through September 30. Twelve Washington State counties were trapped with sticky traps baited with pheromone lures (See Table 2) and fourteen counties had leaf samples taken for disease testing (See Table 3). Traps were checked every two to four weeks and changed at least every four weeks. Leaf samples were taken from grapes vines with yellowing, reddening, blotching, or scorching symptoms in order to test for the plant diseases.